What is RGDiff?
; RADIUS OF GYRATION (RG) : Identifies how fast a ball begins to
rotate once it leaves the bowler's hand. An account of the location
of the mass inside a bowling ball. Rg tells us whether the ball has
the mass toward the center of the ball (low rg), toward the cover
of the ball (high rg) or somewhere in between (medium rg). 1. Low
rg balls rev up quickly. 2. Medium rg balls rev up slightly later.
3. High rg balls lope down the lane saving the energy until
later.
; Differential (of Radius of Gyration) : It is the difference
between the lowest and highest RGs. You compute the high and
subtract the low from that and you have the differential. There is
no minimum for differential. What differential tells you: RG
Differential is an indicator of track flare POTENTIAL in a bowling
ball. Differentials in the .01s to .02s would mean that a ball has
a lower track flare potential, .03s to .04s would be the medium
range for track flare potential, and the .05s to .080 would
indicate a high track flare potential. These ranges above are not
based on cardinal rules. They are BTM in-house rules of thumb
because there are no published guidelines. Also, differential is a
guide to the internal versatility of a ball. It can indicate just
how much of a length adjustment can be made through drilling. A low
differential will allow for only a modest variance in length (from
shortest drilling to longest) which may translate into as little as
a foot or two. An extremely high differential may translate into a
length window in the neighborhood of eight feet.